Marilyn Nieves/iStock(DALLAS) — In a homicide case that sparked days of protests in Dallas and calls for justice from the victim’s family in the Caribbean, a former police officer is expected to go on trial Monday, accused of fatally shooting a 26-year-old unarmed black man after mistaking his apartment for her own and wrongly suspecting he was a burglar.

Amber Guyger, who is white and a former Dallas police officer, is charged with murder stemming from the Sept. 6, 2018, fatal shooting of Botham “Bo” Jean at the South Side Flats apartment complex in Dallas.

“Anytime you bring a case against a police officer it’s difficult anywhere in the country because there’s so much automatic credibility given to law enforcement officers,” Lee Merritt, an attorney representing Jean’s loved ones, told ABC News on Sunday.

Merritt said he is hoping the judge presiding over the case rejects Guyger’s attempt to use Texas’s Castle Doctrine as a defense. Similar to Florida’s “stand your ground” law, the Castle Doctrine allows people to use lethal force to defend themselves from harm that presents itself in the comfort of their own home.

“Of course that’s tricky because we know Amber Guyger was not in her own home,” Merritt said.

He said if the judge refuses to instruct the jury on the Castle Doctrine, Guyger is likely to be convicted.

Opening arguments in the case are expected to begin Monday after a jury was picked earlier this month to hear the case.

Jean’s family, including his parents, brother and sister, are expected to hold a prayer vigil on the steps of the Dallas courthouse Monday morning before the trial begins, Merritt said.

“We’re hoping to see a diverse jury that’s able to critically analyze testimony from law enforcement officers,” Merritt said.

Guyger, 31, was fired from the Dallas Police Department 18 days after she fatally shot Jean. She had been a member of the department for four years.

She told investigators she arrived home about 10 p.m. after working a 15-hour shift and parked her car on the fourth floor of the building instead of the third floor, which corresponded to her apartment, according to an arrest warrant affidavit by investigators from the Texas Rangers, a division of the Texas Department of Public Safety.

Guyger’s apartment was directly beneath Jean’s fourth-floor unit.

“Guyger entered the building and walked down the fourth-floor hallway to what she thought was her apartment,” according to the arrest warrant. “She inserted a unique door key, with an electronic chip, into the door keyhole. The door, which was slightly ajar prior to Guyger’s arrival, fully opened under the force of the key insertion.”

When the door opened, she saw a “large silhouette” in the nearly completely dark apartment and believed it was a burglar, according to the warrant.

Guyger told investigators she drew her firearm, gave verbal commands that were ignored and fired twice, hitting Jean, who lived alone, in the torso, according to the document.

She was still in her uniform at the time of the shooting.

“Due to the interior darkness of the apartment, Guyger turned on the interior lights while on the phone with 911. Upon being asked where she was located by emergency dispatchers, Guyger returned to the front door to observe the address and discovered she was at the wrong apartment,” according to the arrest warrant.

During his funeral, Jean, who was an accountant for PricewaterhouseCoopers, was recalled by mourners as a man of many talents: a strong Christian, a beloved friend, dependable work colleague and a gifted singer. Jean’s uncle said he had aspirations of becoming a politician in his native country of Saint Lucia.

“The sound of gunshots did not have the resonance to be heard on our small island, but their impact was of nuclear proportions,” Jean’s uncle, Ignatius Jean, told mourners at the funeral. “A nuke had been unleashed on our family by someone charged to protect and serve.”

Guyger was initially arrested and charged with manslaughter. But a Dallas County grand jury later indicted her on one count of murder.

Guyger’s defense team had requested a change of venue for the trial, arguing Guyger couldn’t get a fair trial in Dallas County because of the publicity surrounding the case.

A judge rejected the request.

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